Study design
A prospective cohort study was conducted from November 2014 to April 2017 at the 2nd Department of Pediatrics of the National and Kapodistrian University of Athens at the “P. & A. Kyriakou” Children’s Hospital. The study protocol was approved by the Hospital’s Ethics Committee prior to its initiation (approval number 14445/22-10-2015). Parental informed written consent was obtained prior to enrollment.